FIG. 1 is a structural schematic view of an electrical connector assembly 10 in prior art, which is disclosed in United States patent application publication No. US2016/0365654A1. Referring to FIG. 1, an electrical connector assembly 10 comprises a plurality of electrical connectors 12 and a circuit board 14. The electrical connectors 12 are provided on the circuit board 14. The electrical connector 12 has a height H1 and a width W1, and a value of the height H1 is far larger than a value of the width W1, which makes the centre of gravity of the electrical connector 12 relatively higher. Moreover, a contact area between the electrical connector 12 and the circuit board 14 is in proportion to the width W1. Because the width W1 is relatively smaller, the contact area is relatively small. Because the centre of gravity of the electrical connector 12 is relatively higher and because the contact area between the electrical connector 12 and the circuit board 14 is relatively smaller, before the electrical connector 12 is fixed to the circuit board 14 by a fixing operation (for example, soldering operation), the electrical connector 12 easily shakes and can not be relatively stably placed on the circuit board 14.
FIG. 2 is a structural schematic view of an electrical connector assembly 20 in prior art, which is disclosed in U.S. Pat. No. 9,537,239B1. Referring to FIG. 2, the electrical connector assembly 20 comprises a plurality of card edge connectors 200, a plurality of clamping plates 220 and a lead guide plate 240. The card edge connectors 200 make fixing portions 202 thereof respectively inserted into a plurality of recessed grooves 222 of the clamping plates 220, by which the card edge connectors 200 are connected together. However, when the recessed groove 222 is manufactured, tolerance will be generated unavoidably, which makes a practical size of the recessed groove 222 may be larger than or less than a preset size. So, the fixing portion 202 of the card edge connector 200 may not be firmly inserted into the recessed groove 222 of the clamping plate 220. Therefore, reliability is relative lower. In addition to that the fixing portions 202 of the card edge connector 200 need to be aligned with the recessed grooves 222 of the clamping plates 220, the terminals 204 of the card edge connector 200 also need to be aligned with on apertures of the lead guide plate 240. However, because the tolerances of the recessed grooves 222 of the clamping plates 220 result in that a pitch between every two adjacent card edge connectors 200 is not consistent, a pitch between inserting ends of the terminals 204 is not consistent either, which results in that the inserting ends of the terminals 204 can not be aligned with the apertures. So, assembling is not relatively easy.
FIG. 3 is a structural schematic view of an electrical connector assembly 30 in prior art, which is disclosed in U.S. Pat. No. 7,993,147B2. Referring to FIG. 3, the electrical connector assembly 30 comprises a shroud 300 and a contact module 310. The shroud 300 comprises card edge slots 302, 304. However, there is a solid face 306 between the two card edge slots 302, 304, therefore heat dissipation is relatively worse.